Field of the Invention
The present invention relates to modular cartridge ammunition for rifle and handguns having reusable cases and projectiles and includes variations for practice, training, and self-defense. The present invention also relates to systems of such modular cartridge ammunition.
Background of the Art
Ammunition for rifles and handguns—collectively referred to herein as “small arms”—is modernly provided in the form of cartridges. Although cartridges come in many configurations and sizes, a typical center-fire cartridge 100 is show in cross-section in FIG. 1.
The cartridge 100 includes a projectile 102 (which is commonly referred to as a “bullet”), an expansive case 104 (which is commonly referred to as a “casing” or a “shell”), propellant 106 (which is commonly referred to as “gun powder”), and a primer 108 (which is commonly referred to as a “cap” or “primer cap”). The projectile 102 is nested in a cavity at the discharge end 110 of the case 104 and held in place by circumferentially crimping the wall 112 of the case 104 against the projectile 102. The primer 108 is press-fit into a primer-receiving cavity 114 at the striking end 116 of the case 104. A small passageway called a flash-hole 118 extends through the end wall of the primer-receiving cavity 114 to provide communication between the primer-receiving cavity 114 and the propellant 106. A flanged rim 120 extends circumferentially around the striking end 116 of the case 104 to help seat the cartridge 100 in the breech chamber of the small arm in which it is to be used. The exterior of the cartridge 100 is sized to fit into the small arm with which it is intended to be used and to provide predetermined levels of gas sealing during firing.
To fire the cartridge 100, it is first loaded into the breech chamber of the small arm and then locked into place. Pulling the trigger of the small arm causes a firing pin to strike against the striking end of the primer 108 to produce a concussion which causes the pressure-sensitive explosive which is contained within the primer 108 to explode. The hot gases and sparks produced by the explosion travel through the flash-hole 118 and ignite the propellant 106 which rapidly conflagrates to produce a high pressure gas pulse against the base 122 of the projectile 102 while causing the casing 104 to radially expand thus loosening its connection with the projectile 102. Propelled by the high pressure gas pulse, the projectile 102 is accelerated to high speed as it travels through and out of the barrel of the small arm. The reactive force that corresponds to discharge of the projectile 102 pushes the small arm backwards toward the shooter. A portion of this reactive force is used in many small arms to operate a mechanism that removes the now empty case 104 from the small arm's breech and inserts another cartridge in its place ready for firing.
Small arms ammunition cartridges are typically machine assembled. The primers and projectiles are typically designed for one-time use while the cases are often reconditioned and reused in machine-assembled cartridges or in user-reloaded cartridges assembled using hand-operated presses.
For a given small arm, the amount of propellant and the design and type of the projectile are selected based upon the intended use of the shooter. For uses in which lethal force is desired, cartridges having heavy projectiles which are accelerated to high muzzle velocities by large amounts of propellants and high pressure primers are often chosen. For target practice and training uses, light, round-tip projectiles are typically used and the amount of propellant may be reduced or even eliminated altogether to lower the muzzle velocity of the projectile. In some training uses, even the projectile is eliminated. Thus, since each kind of shooting use is best satisfied by a cartridge having characteristics tailored to that use, a wide variety of cartridges are available for the typical small arm. However, it is costly to acquire and stock a variety of cartridges for a variety of uses.
As is discussed in more detail in the Summary of the Invention and the Detailed Description of Preferred Embodiments sections below, the present invention makes small arm cartridge ammunition more affordable by providing modular cartridges that may be hand-assembled by the ultimate user. Although there have been many attempts in the past to satisfy this long-felt need of lower-cost user-assembled cartridge ammunition, none of the attempts have yielded all of the advantages which are produced by the present invention. In general, each of the previous attempts provided a single type of cartridge which was useful only for short-range target practice. In contrast, the present invention provides a wide variety of cartridges to satisfy a wide variety of uses. A few of the more notable previous attempts will now be discussed in the chronological order of their development.
In 1880, U.S. Pat. No. 228,494 was issued to B. E. Valentine for a 0.50 caliber or larger rifle cartridge that was suited for training purpose and short ranges. The cartridge is described therein as a “compound cartridge” because it consisted of an outer case that was sized to fit the rifle breech chamber and an inner case that was inserted into the striking end of the outer case. The inner case was a smaller caliber blank cartridge. No propellant was used other than that which was contained in the blank cartridge. It was not necessary to fix the projectile into the cartridge and the projectile could even be loaded through the muzzle end of the rifle after the compound casing had been breech loaded into the rifle. If a space was left between the end of the inner case and the base of the projectile, sawdust or wads of pasteboard or felt could be placed therebetween.
In 1904, Great Britain Patent No. 10,288 was issued to W. H. Trask for rifle cartridge that consisted of an outer case which was dimensioned to fit the rifle chamber. The outer case had a recess at its striking end for receiving an inner case in the form of a blank cartridge which was to be “inserted with the thumb and fingers, and pressed home as far as it would go.” No propellant was to be used other than that which was contained in the blank cartridge. A short lead projectile was to be inserted in the firing end of the outer case “with the fingers.” The cartridge was “best suited for the usual indoor range of 25 to 50 yards” but was said to provide “splendid shooting” at up to 100 yards or more. Nonetheless, it is clear from the small powder charge and the small projectile that this cartridge was suitable only for target practice.
In 1933, U.S. Pat. No. 1,902,771 was issued to A. F. Gaidos for a “practice cartridge” which was described as being preferably used “in short range target practice or small game hunting.” Actually, Gaidos disclosed two different small arms cartridge designs (plus a third for use with a “small cannon”). The first cartridge design was similar to the cartridges of Valentine and Trask mentioned above, in that it used an outer case that fitted the gun's breech chamber and an inner case which comprised a blank that was fitted by hand into a recess of the outer case. This cartridge used no propellant other than that contained in the blank cartridge. The projectile could be seated by hand into the outer case using an alignment fixture. Gaidos' second cartridge design was like the conventional cartridge 2 of FIG. 1 as described above in all respects except two. The first was that it had a two-piece case consisting of a first piece which was hollow and generally cylindrical and a second striking end closure piece that threaded onto the forward piece. The closure end piece had a recess which held a primer. This cartridge was assembled by introducing a projectile having a flared base into the rear open end of the forward piece of the case and sliding the projectile through forward piece until it seated against an internal shoulder of the forward piece. The hollow of the forward piece could then be loaded with a desired amount of propellant. Finally, the closure piece was screwed onto the end of the forward piece of the case.
In 1959, U.S. Pat. No. 3,060,856 was issued to J. S. Dunn for a “practice round of ammunition.” Dunn's cartridge used only a primer as its source of projectile propelling force. Externally, the case of the cartridge was sized to fit the breech chamber in which it was to be used. Internally, the case had a first chamber for receiving the straight-walled narrow neck of a shouldered projectile, a second chamber for receiving a primer, and a narrow venturi beveled outwardly at both ends which was situated between the first and second chambers. The second chamber had on its striking end side a snap rim to hold the primer in place. No propellant was used. Both the case and the projectile were made of a moldable plastic. The projectile was to be somewhat softer than the case to facilitate the insertion and sealing of the projectile in the case. The projectile was said to be “reusable for about fifty shots without requiring extensive recovery operations or the use of special tools thereon.” The primer was to be inserted and removed with an awl or ice pick.
In 1983, U.S. Pat. No. 4,391,199 was issued to L. Morin for “safe ammunition for exhibition and target shooting.” The ammunition comprised a plastic charge carrier, a holder, and a hollow plastic projectile. The charge carrier nested within the holder and had a central collar that engaged the holder's interior walls. Extending in opposite directions from the central collar was a nose end that had closed cone tip and a tail end which held a primer. The charge carrier also had a cylindrical chamber which extended between its tail and nose ends for holding a desired amount propellant. The charge carrier's nose nested within the hollow rear end of the projectile and connected the charge carrier to the projectile. During a shot, the charge carrier's nose split off along fracture line at the charge carrier's collar and was carried away with the projectile while the rest of the charge carrier remained in the gun with the base. The projectile was said to be reusable one time.
In 1993, U.S. Pat. No. 5,259,319 was issued to R. Devecky et al. for “reusable training ammunition.” Although described to be used with 37 millimeter gas guns and 40 millimeter grenade launchers rather than small arms, mention is made here of this ammunition because of some features it shares with the hand-reloadable ammunition described above. Like the cartridges of Valentine and Trask, and the first cartridge design of Gaidos, the Devecky et al. cartridge used an outer case that fitted the breech chamber for which it was intended and an inner case which comprised a blank cartridge that was fitted by hand into a recess of the outer case and made use of no propellant other than that which was contained in the blank cartridge. Internally, the Devecky et al. outer case had four straight-walled interconnecting shouldered cylindrical chambers of decreasing radius which were interposed between its firing end and its blank-receiving recess. The projectile had hollow cylindrical chamber running from its tail end forward for about two-thirds of its length. The projectile had a three-step neck at its tail end. The first step was a short steep-angle bevel, the second step was a long shallow-angle bevel, and the third step was a short flat cylinder which stopped at the shoulder formed by the bottom of the forward section of the projectile. These steps permitted the neck to nest within the outer case's interconnecting chambers of decreasing radius without engaging their walls or the shoulders at their junctions. An o-ring was seated on the neck in a groove at the intersection of the second and third steps. This o-ring provided a seal and a resilient connection between the outer case and the projectile. Optionally, an o-ring groove could be provided in the inside wall of the outer case for receiving the o-ring when the projectile neck was properly nested with the outer case. Also, optionally, one or more o-rings could be seated in o-ring grooves on the forward portion of the projectile so as to act as “spin rings” which would engage rifling grooves of the gun's barrel as the projectile traveled down the barrel after being shot away from the case. The case and projectile were to be made of durable impact-resistant materials so as to be reusable.